Magnetic device



Fb. 1s, 1958 A. SKROBISCH MAGNETIC DEVICE Fi'led Jan. 2l, 1955 United States Patent O MAGNETIC DEVICE Alfred Skrobiseh, New York, N. Y., assigner to Allard Instrument Corp., New York, N. Y., a corporation of New York Application January 21, 1955, Serial No. 483,260

11 Claims. (Cl. 20G-87) This invention relates to magnetic devices, and more particularly to a sensitive magnetic device which may be used as an annunciator, indicator, relay, or circuit breaker.

The primary object of the present invention is to generally improve small light weight sensitive magnetic devices of the specified character. A more particular object is to provide such a device in which the moving parts are rotational, and are balanced both statically and dynamically, thereby making the same shock resistant and vibration resistant, and suitable for use in aircraft,

To accomplish the foregoing general objects, and other more specific objects which will hereinafter appear, my invention resides in the armature, magnet, and indicator elements, and their relation one to another, as are hereinafter more particularly described in the following speciiication. The specification is accompanied by drawings in which:

Fig. l is a side elevational View of a rotary indicator and relay embodying features of my invention;

Fig. 2 is an end View thereof looking toward the indicator;

Fig. 3 board;

Fig. 4 is a side elevation drawn to larger scale, with the cover plate removed;

Fig. 5 corresponds to a fragment of Fig. 4, and shows the relay contact in raised position;

Fig. 6 is a vertical section through the forward part of the device;

Fig. 7 is a similar view, but showing the relation of the parts when the coil is energized;

Fig. 8 is a transverse section taken approximately in the line 8 8 of Fig. 4;

Fig. 9 is a plan view of the rotor;

Fig. l0 is a section through the rotor taken approximately in the line lil-16 of Fig. 9; and

Fig. ll is a horizontal section through the forward part of the device with the rotor and armature removed.

Referring to the drawings, and more particularly to Fig. 4, the magnetic device comprises a rotor 12 and a rotor spring 14 biasing the rotor in one direction, in this case, cotmterclockwise. lt further comprises an armature 16 pivoted at l and having an edge 2t) (Fig. 6) movable into or out of the path of a stop ledge 22 forming a part of the rotor 12. There is also a magnet coil 24 and a frame 2-6 for establishing a magnetic circuit through the armature 16. The armature is normally biased in a clockwise direction by means of an armature spring 28. The arrangement is such that energization of the coil 24 turns the armature against the force of the spring 23 and so moves the edge 2t? of the armature relative to the stop edge 22. in the arrangement here shown it moves the edge away from the stop ledge 22, as shown by the change from Fig. 6 to Fig. 7, thereby releasing the rotor 12 for movement by the rotor spring 14.

In Fig. 4 it will be seen that the parts are contained within an elongated housing 3i), with the rotor 12 exis an end View looking toward the terminal V2,824,188 Patented Feb. 18, s

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posed at the forward end of the housing. The coil 24 is elongated in conguration, and it occupies the rear portion of the housing for much of the length of the housing. The armature 16 is located between the rotor 12 and the coil 24, and the pivot 18 of the armature is preferably parallel to the pivot pin 32 of the rotor. The exposed forward part of the rotor preferably has a roughened proiection 34 which may be used as a finger piece to move the rotor back` from the position shown in Fig. 7 to that shown in Fig. 6.

ln Figs. 6 and 7 it will be observed that the magnetic circuit includes an upper pole piece 36 and a lower pole piece 3S. The upper pole piece is disposed on one side of one end of the armature 16, while the lower pole piece 3f is disposed on the other side of the other end of the armature. The armature spring 28 acts to open the magnetic or flux path. On energization of the coil 24 the armature is attracted to the pole pieces, thus turning the armature and closing the gaps as shown in Fig. 7. The armature and the pole pieces are disposed at an angle, say about 45, thus bringing the forward edge 20 of the armature into working relation with the rotor.

As so far described, the device may be used as an indicator or annunciator, and for that purpose a part of the rotor, in this case the upper part marked 40 in Fig. 7, is coated with a distinctive color, for example, white, while the plastic out of which the rotor is molded may be dark brown or black. Thus the front end of the indicator will change from dark as in Figs. l, 2, 4 and 6, to light as in Fig. 7, when the coil 24 is energized. When used in this fashion, as an indicator, only two pins or terminals are needed for electrical connection to the coil These are the pins 42 and 44 best shown in Fig. 3. The pins are mounted on a suitable insulation terminal board 46, which is fixed at the rear end of the housing 30.

To use the device as a relay or as a circuit breaker, l add a movable contact arrangement which may be described with reference to Figs. 4 and 8 of the drawings. An insulation block 5@ carries two stationary contacts 52 and 54, and a movable contact arm 56. The latter may be made of wire which is bent at right angles to pass through the insulation at 58. lt is so shaped that it will engage either Contact 52 in its down position, as shown in Fig. 4, or contact 54 in its up position, as shown in Fig. 5. lt is preferably made of spring metal, and normally moves upward to the position shown in Fig. 5.

ln Figs. 4 and 9 it will be seen that one end of the rotor is provided with a generally radial operating nger 60. When the rotor is in the position shown in Fig. 4 the linger 6@ engages and bears down on the forward free end of the movable contact 56. However, when the coil 24 is energized, thereby releasing the rotor to move to the position shown in Fig. 7, the movable contact 56 rises to engage the contact 54 as shown in Fig. 5.

ln Fig. 4 it will be seen that three wires generally designated 62, lead back from the relay contacts along side of the coil 24. These wires are connected at their rear ends to three terminals designated 64, the said terminals being mounted on the terminal board 46, previously referred to.

Considering the structure in greater detail, the housing 36 is preferably cast out of aluminum and consists of a top wall 7th (Fig. 8), a side wall 72 and a bottom wall 74. The housing is completed by an aluminum plate or cover 76 (Figs. l and 2) which is secured in position by means of four small screws 78. The aluminum housing preferably includes upstanding ears 86 for attachment to a panel, a fragment of which is indicated at 82 in Fig. l.

The forward end of the housing is closed by the rotor 12, and this preferably consists of a single piece of molded insulation, such as nylon. The rotor, as molded, includes the finger piece 34, the ledge 22 and the relay 3 finger 60. The rotor is at least partially hollow, thus providing room for the spring 14, one end of which is received in a hole in the aluminum housing, and the other end of which is received in a hole in the rotor. The rotor is balanced because the ledge 22 and finger 60 come about opposite the finger piece 34, but, in addition, appropriate holes may be, and preferably are, drilled in the rotor to provide a more accurate balance of the same about its pivot pin 32. The latter is a metal pin driven into the side wall 72 of the housing, as is best shown in Fig. l1, the said wall preferably being thickened at the pin 32, as shown at 84.

A part of the housing acts as a stop to limit upward movement of the finger piece 34. It projects forward at 86 to prevent accidental or intentional exertion of downward force on the finger piece 34, which would put an undesired strain on the parts including the pivot pin iS of the armature 16. When the rotor is released its downward movement is limited by the lower part S8 of the housing. At this time the finger 34 is exposed for upward or restoring movement, which movement is intended to be caused manually.

The magnet coil 24 in this particular case is wound with 14,000 turns of a No. 38 GaSF wire. This data is given by way of example, and not in limitation of the invention. The resulting indicator or relay is sensitive to a current of only six milliamps or less, and a power of only l@ of a watt.

The magnetic circuit includes a ferrous core 90 passing through the coil, the rear end of which is riveted at 92 to the downwardly turned part 94 of a ferrous metal strip 96 forming a main part of the magnet frame. The forward end of the strip 95 is bent down to provide the pole piece 36 previously referred to. The forward end of the core 90 is riveted at 98 to another piece of ferrous strip, which is bent at right angles, and which provides the pole piece 33 previously referred to. The forward edge of this pole piece is preferably Cut at an angle corresponding to the angle of the armature which, in this case, is about 45.

Between the coil 24, and the forward pole piece 38, one wall of an angular brass bracket 100 is secured. The side wall of this bracket is upright, as indicated at 102 in Fig. l1, and it serves to Xedly carry one end of the pivot pin 18 of the armature. The other end of pin 18 is grooved as shown in Fig. ll, to receive a split washer shown in Fig. 4. A screw 104 passes through .bracket wall 102 into the side wall 72 of the housing, and thus serves to hold the magnet in position. The opposite end of the magnet is held in position by an ear 106 (Fig. 4) receiving a screw 10S. The screw 104 also holds a stop arm lit) which limits the opening or release movement of the armature. This movement may be quite small, it being only 0.02.

lf desired, the central part of the top member 96 of the magnet frame may be longitudinally slotted or cut away, as is indicated at 114 in Figs. 6 and 7. The amount of metal left is kept adequate for the flux to be carried. The cross wall 100 of the brass bracket may be projected upwardly. to be received in the slot 114, as shown at 1216 in Fig. S, thereby better locking the bracket against possible rotation about the core 90.

The aluminum housing 30 is cast with shouldered portions 11S against which the terminal board 46 is secured, as by means of four small drive screws 11.20. The shoulders 118 also provide metal in which threaded holes are formed to receive the screws 78 shown in Fig. l.

The insulation block 50 carrying the relay contacts is secured in position by means of two small screws 122 (Figs. 4 and 8). The stationary contacts 52 and 54 are pieces of wire passing through the block, and bent upwardly inside the block to receive the ends of wire 62.

it will be understood that when the device is to be used solely as an indicator or an annunciator the relay parts, including the insulation block 50 with its stationary and movable contacts, may be omitted, along with the screws 122 and the three terminals 64. It will also be understood that the relay may act as a single pole double throw switch, or a single pole single throw switch. In the latter case one of the three terminals 64 is not used. Also, when the device is used as a circuit breaker one of the terminals '34,- need not be used. The circuit breaker, of course, is resettable by simply moving the rotor back up from the position shown in Fig. 7 to that shown in Fig. 6, and it will, therefore, be understood that the stationary contact S4 is used in the protected circuit.

is believed that the construction and method of use of my improved magnetic device, as well as the advantages thereof, will be apparent from the foregoing detailed description. There are only two moving parts, and these have only a slight movement and may be, and preferably are, balanced both statically and dynamically. The particular device shown is only three-quarters of an inch square and three inches in length, and thus is compact, as well as light in weight. The device is shock and vibration resistant, and yet is highly sensitive, being responsive to a power of only 17%,@ of a watt.

it will be apparent that while I have shown and described my invention in a preferred form, changes may be made in the structure disclosed, without departing from the scope of the invention as sought to be dened in the following claims.

I claim:

l. A sensitive magnetic device comprising a balanced rotor, a rotor spring biasing the rotor in one direction, a stop ledge on the inner face of the rotor, a balanced armature pivoted between its ends and having one edge movable into and out of the path of the stop ledge, a magnet coil and frame for establishing a magnetic circuit through the armature, and an armature spring normally biasing the armature in a direction to open the magnetic circuit, whereby energization of the coil turns the armature against the force of the spring and so moves the edge of the armature relative to the stop ledge, the magnet frame terminating in pole pieces, one of which is disposed on one side of one end of the armature, and the other edge of which is disposed on the other side of the other end of the armature, and the exposed end of the armature cooperating with the stop ledge of the rotor as aforesaid, whereby energization of the coil turns the armature.

2. A sensitive magnetic device comprising a balanced rotor, a rotor spring biasing the rotor in one direction, a stop ledge on the inner face of the rotor, a balanced armature pivoted between its ends and having one edge movable into and out of the path of the stop ledge, said armature being approximately tangential to the rotor, a magnet coil and frame for establishing a magnetic circuit through the armature, and an armature spring normally biasing the armature toward the rotor and in a direction to open the magnetic circuit, whereby energization of the coil turns the armature against the force of the spring and so moves the edge of the armature away from the stop ledge in order to release the rotor for movement by the rotor spring, the magnet frame terminating in pole pieces, one of which is disposed on one side of one end of the armature, and the other edge of which is disposed on the other side of the other end of the armature, and the exposed end of the armature cooperating with the stop ledge of the rotor as aforesaid, whereby energization of the coil turns the armature.

3. A sensitive magnetic device comprising a balanced rotor, a rotor spring biasing the rotor in one direction, a stop ledge on the inner face of the rotor, a balanced armature having one edge movable into and out of the path of the stop ledge, a magnet coil and frame for establishing a magnetic circuit through the armature, and an armature spring normally biasing the armature in a direction to open the magnetic circuit, whereby energization of the coil turns the armature against the force of the spring and so moves theredge of the armature relative to the stop ledge, the magnet frame terminating in pole pieces, one of which is disposed on one side of one end of the armature, and the other edge of which is disposed on the other side of the other end of the armature, and the exposed end of the armature cooperating with the stop ledge of the rotor as aforesaid, whereby energization of the coil turns the armature, the parts being contained within an elongated housing, with a part of the rotor exposed at the forward end of the housing, the coil being elongated in contiguration and occupying the rear portion of the housing for much of its length, and the armature being located between the rotor and the coil, said rotor and armature having parallel pivot pins, and the exposed part of the rotor at the front of the device having a roughened projection acting as a ngerpiece to move the rotor.

4. A sensitive magnetic device comprising a balanced rotor, a rotor spring biasing the rotor in one direction, a stop ledge on the inner face of the rotor, a balanced armature having one edge movable into and out of the path of the stop ledge, a magnet coil and frame for establishing a magnetic circuit through the armature, and an armature spring normally biasing the armature in a direction to open the magnetic circuit, whereby energization of the coil turns the armature against the force of the spring and so moves the edge of the armature rela tive to the stop ledge, the magnet frame terminating in pole pieces, one of which is disposed on one side of one end of the armature, and the other edge of which is disposed on the other side of the other end of the armature, and the exposed end of the armature cooperating with the stop ledge of the rotor as aforesaid, whereby energization of the coil turns the armature, and further comprising a movable contact cooperating with two stationary contacts in order to engage one or the other, the movable end of said movable contact extending forward to a position near the rotor, and said rotor including a radially projecting finger to engage and move the movable contact.

5. A sensitive magnetic device comprising a balanced rotor, a rotor spring biasing the rotor in one direction, a stop ledge on the inner face of the rotor, a balanced armature having one edge movable into and out of the path of the stop ledge, a magnet coil and frame for establishing a magnetic circuit through the armature, and an armature spring normally biasing the armature in a direction to open the magnetic circuit, whereby energization of the coil turns the armature against the force of the spring and so moves the edge of the armature relative to the stop ledge, the magnet frame terminating in pole pieces, one of which is disposed on one side of one end of the armature, and the other edge of which is disposed on the other side of the other end of the armature, the pole pieces and armature being disposed at an angle of about 45, and the exposed end of the armature cooperating with the stop ledge of the rotor as aforesaid, whereby energization of lthe coil turns the armature.

6. A sensitive annunciator or indicator comprising a balanced rotor acting as the indicator element, a rotor spring biasing the rotor in one direction, a stop ledge on the inner face of the rotor, a balanced armature having one edge movable into and out of the path of the stop ledge, a magnet coil, core and frame for establishing a magnetic circuit through the armature, and an armature spring normally biasing the armature toward the rotor and in a direction to open the magnetic circuit, whereby energization of the coil turns the armature against the force of the spring and so moves the edge of the armature away from the stop ledge in order to release the rotor for movement by the rotor spring, the magnet frame terminating in pole pieces, one of which is disposed on one side of one end of the armature, and the other edge of which is disposed on the other side of the other end of the armature, the pole pieces and armature being disposed at an angle of about 45, with the armature approximately tangential to the rotor, and

6 the exposed end of the armature cooperating with the aforesaid stop ledge of the rotor, whereby energization of the coil turns the armature away from the rotor and releases the rotor for movement by its spring.

7. A sensitive magnetic device comprising a balanced rotor, a rotor spring biasing the rotor in one direction, a stop ledge on the inner face of the rotor, a balanced armature pivoted between its ends and having one edge movable into and out of the path of the stop ledge, a magnet coil and frame for establishing a magnetic circuit through the armature, and an armature spring normally biasing the armature in a direction to open the magnetic circuit, whereby energization of the coil turns the armature against the force of the spring and so moves the edge of the armature relative to the stop ledge, the parts being contained within an. elongated housing, with a part of the periphery of the rotor exposed at the forward end of the housing, the coil being elongated in configuration and occupying the rear portion of the housing for much of its length, and the armature being located between the rotor and the coil, said rotor and armature having parallel pivot pins, and the exposed part of the rotor at the front of the device having a roughened projection acting as a tingerpiece to move the rotor.

8. A sensitive magnetic device comprising a balanced rotor, a rotor spring biasing the rotor in one direction, a stop ledge on the inner face of the rotor, a balanced armature pivoted between its ends and having one edge movable into and out of the path of the stop ledge, a magnet coil and frame for establishing a magnetic circuit through the armature, and an armature spring normally biasing the armature in a direction to open the magnetic circuit, whereby energization of the coil turns the armature against the force of the spring and so moves the edge of the armature relative to the stop ledge, the parts being contained within an elongated housing, with a part of the periphery of the rotor exposed at the forward end of the housing, the coil being elongated in configuration and occupying the rear portion of the housing for much of its length, and the armature being located between the rotor and the coil, said rotor and armature having parallel pivot pins extending transversely of the axis of the coil and housing, with the armature approximately tangential to the rotor, and the exposed part of the rotor at the front of the device having a roughened projection acting as a fingerpiece to move the rotor.

9. A sensitive annunciator or indicator comprising a balanced rotor acting as the indicator element, a rotor spring biasing the rotor in one direction, a stop ledge on the inner face of the rotor, a balanced armature pivoted between its ends and having one edge movable into and out of the path of the stop ledge, a magnet coil, core and frame for establishing a magnetic circuit through the armature, and an armature spring normally biasing the armature toward the rotor and in a direction to open the magnetic circuit, whereby energization of the coil turns the armature against the force of the spring and so moves the edge of the armature away from the stop ledge in order to release the rotor for movement by the rotor spring, the parts being contained within an elongated housing, with a part of the rotor exposed at the forward end of the housing, the coil being elongated in configuration and occupying the rear portion of the housing for much of its length, and the armature being located between the rotor and the coil, said rotor and armature having parallel pivot pins extending transversely of the axis of the coil and housing, the pole pieces and armature being disposed at an angle of about 45 relative to the axis of the coil and housing, with the armature approximately tangential to the rotor, and the exposed part of the rotor at the front of the device having a roughened projection acting as a fingerpiece to move tl e rotor.

1G. A sensitive magnetic device comprising a balanced rotor, a rotor spring biasing the rotor in one direction, a stop ledge on the inner face of the rotor, a balanced armature pivoteo between its ends and having one edge movable into and out of the path of the stop ledge, a magnet coil and frame for establishing a magnetic circuit through the armature, and an armature spring normally biasing the armature in a direction to open the magnetic circuit, whereby energization of the coil turns the armature against the force of the spring and so moves the edge of the armature relative to the stop ledge, and a movable contact cooperating with two stationary contacts in order to engage one or the other, the movable end of said movable contact extending forward to a position near the rotor, and said rotor including a radially projecting finger to engage and move the movable contact.

11. A sensitive annunciator or indicator comprising a balanced rotor acting as the indicator element, a rotor spring biasing the rotor in one direction, a stop ledge on the inner face of the rotor, a balanced armature pivoted between its ends and having one edge movable into and out of the path of the stop ledge, with the armature approximately tangential to the rotor, a magnet coil, core and frame for establishing a magnetic circuit through the armature, and an armature spring normally biasing the armature toward the rotor and in a direction to open the magnetic circuit, whereby energization of the coil turns the armature against the force of the spring and so moves the edge of the armature away from the stop ledge in order to release the rotor for movement by the rotor spring, and a movable contact cooperating with two stationary contacts in order to engage one or the other, the movable end of said movable contact extending forward to a position near the rotor, and said rotor including a radially projecting finger to engage and move the movable contact.

References Cited in the tile of this patent UNITED STATES PATENTS 650,915 Scribner et al. `lune 5, 1900 741,115 Dean Oct. 13, 1903 784,635 Setter Mar. 14, 1905 1,104,077 Smith July 21, 1914 1,118,454 Weeks Nov. 24, 1914 1,987,495 Soulat Jan. 8, 1935 2,427,998 Wilchens Sent. 23, 1947 

